Neonatal lung function in very immature infants with and without RDS

Abstract

Some infants, despite being born at low gestations (< 28 weeks gestational age) do not develop RDS and are not surfactant treated. The changes in lung function during the neonatal period in such infants have not been explored, hence it is unknown whether they are similar to those of surfactant treated infants with RDS of similar gestational age. Such data would facilitate assessment of the impact of surfactant administration on the lung function abnormalities of very immature infants with RDS. We, therefore, compared the results of neonatal lung function measurements from immature infants with RDS who received surfactant to those from infants with non-RDS respiratory distress not so treated and matched to the RDS infants for gestational age and within 10% of birthweight. Compliance and functional residual capacity (FRC) were measured daily for the first five days and then at 1, 2 and 4 weeks in 16 infants, median gestational age 27 weeks (range 25-27 weeks). Although exogenous surfactant administration to the immature infants with RDS was associated with improvements in lung function, the non RDS, non surfactant treated infants had both higher compliance (p < 0.05) and lung volumes (p < 0.01) throughout the perinatal period. These results demonstrate surfactant administration does not fully correct the perinatal lung function abnormalities of very immature infants with RDS.

Respiratory mechanics in ventilated preterm infants: early determinants and outcome

“…62 Also after a precipitous delivery the risk is increased. 136 When corrected for gestational age, the occurrence of RDS is significantly increased in gestational diabetes and in insulin-dependent mothers. 218 Similarly, overnourished infants who are large for gestational age without evidence of maternal diabetes seem to be at increased risk.…”

“…145 Incidence is also increased in male sex, the second-born of twins, Caucasian race when compared to the negroid race, 33 and in situations of cold stress and asphyxia. 136 …”

“…Characteristically, infants are cyanotic in room air with expiratory grunting, tachypnoea, subcostal and intercostal retractions, nasal flaring, and duskiness appearance. 107,136 The increasing cyanosis is often relatively unresponsive to oxygen administration. 136 Respiratory rate is well above the normal range of 30 to 60 per minute to maintain adequate alveolar ventilation at low tidal volumes due to increased stiffness of the lung.…”

“…107,136 The increasing cyanosis is often relatively unresponsive to oxygen administration. 136 Respiratory rate is well above the normal range of 30 to 60 per minute to maintain adequate alveolar ventilation at low tidal volumes due to increased stiffness of the lung. The usually prominent expiratory grunting is caused by partial closure of the glottis to maintain lung volume and gas exchange during exhalation.…”

“…107 Breath sounds during auscultation may be normal or diminished with a harsh tubular quality, and, on deep inspiration, fine rales may be heard, especially over the lung bases posteriorly. 136 Blood gas and acid-base values are characterized initially by hypoxemia and later by progressive hypoxemia, hypercarbia, and variable metabolic acidosis. Within 6-12 hours typical radiological abnormalities may develop at the chest radiograph, which can be graded according to a system described by Giedion and colleagues comprising of four stages.…”